Lubricant cooling system for sewing apparatus



Dec. 30, 1969 R. L. KOSROW ET AL 3,486,474

LUBRICANT COOLING SYSTEM FOR SEWING APPARATUS Filed March 1, 1968 5 Sheets-Sheet l 30, 195-9 R. L. KOSROW ET AL 3,486,474

LUBRICANT COOLING SYSTEM FOR SEWING APPARATUS Filed March 1,. 1968 3 Sheets-Sheet 2 A ,f i I W m 5, m ml Dec. 30, 1969 R. L. KOSROW ET AL 3,486,474

LUBRICANT COOLING SYSTEM FOR SEWING APPARATUS Filed March 1, 1968 3 Sheets-Sheet 5 United States Patent ()fitice 3,486,474 Patented Dec. 30, 1969 3,486,474 LUBRICANT COOLING SYSTEM FOR SEWING APPARATUS Robert L. Kosrow and James J. Matias, Hoffman Estates, and Arthur N. Hale, Park Ridge, Ill., assignors to Union Special Machine Company, Chicago, 111., a corporation of Illinois Filed Mar. 1, 1968, Ser. No. 709,544 Int. Cl. D05b 71/00; F16n 7/00; F28d 15/00 US. Cl. 112-256 12 Claims ABSTRACT OF THE DISCLOSURE Offsetting heat generated by continuous high speed operation of a sewing machine. Involves the continuous withdrawal of lubricant from a reservoir within the frame of the machine, the passage of said lubricant through tubing providing a long path extending upwardly and downwardly in a series of parallel loops provided within an enclosed chamber, cooling the lubricant as it passes through said tubing by a constant flow of relatively cool air through said chamber to effect heat exchange through the walls of said tubing, and returning the cooled lubricant to said reservoir. This circulation of the lubricant is continuous upon the closing of a switch, whether or not the sewing machine is in operation.

This invention relates to means for preventing objectionable overheating of portions of a sewing machine as a result of substantially continuous, high speed operation over a relatively long period of time.

It has been found that industrial sewing machines of types that are operated at high speeds, in excess of 5,000 r.p.m., have a tendency to heat up in various regions, including one adjacent the stitch forming zone, to a temperature as high as 150 F., or even higher. This has frequently led to injury to the operator, whose hand may come in contact with such a hot surface in the course of manipulating the work.

In accordance with the present invention, it has been found possible to keep all portions of the machine at a temperature of 25 F. to 40 F. lower than that normally attained in the course of substantially continuous operation of the machine at high speed for a number of hours. While efforts toward this end have been made heretofore, the means provided for this purpose have not been successful in achieving the desired end result in present day high speed operations of machines over long periods of time. Such continuous and high speed operation is required to keep up with the demand for sewn items these days, and to maintain the cost of producing said items at a reasonable level. Various schemes that have been proposed and used heretofore have been adequate to insure proper lubrication of the mechanism of the machine, but they have not overcome the objectionable discomfort and harm to the operator of the machine. When the metal of the frame structure is permitted to rise to a temperature around 150 F. in certain areas, the radiating heat becomes very uncomfortable to the operator and, as stated above, it has been found to burn the hands of the operator whenever they are brought into contact with such a hot surface, in the course of guiding or handling the work.

Various studies that have been made in connection with the development of the present invention have indicated, firstly the regions of a sewing machine which have the greatest tendency to become overheated, and secondly the extent to which such overheating has been overcome by the use of the special combination of features embodied in the present invention.

One of the primary features of the present invention involves the provision of a pump for continuously withdrawing lubricant from the reservoir within the machine, then passing such withdrawn lubricant through a heat exchange radiator system for reducing the temperature of the lubricant about 30 F. or more, and then returning the cooled lubricant to the reservoir within the sewing machine. The group mentioned is driven by a motor which is separate from that generally referred to as the electric transmitter motor, so that the circulation of the lubricant is continuous and does not stop whenever the sewing machine stops. The radiator system involves a substantial length of tubing which is looped into a relatively large number of upwardly and downwardly extending portions through which the lubricant is forced by the pump from one end of the tubing to the other, and it is delivered from the latter back into the reservoir.

Various expedients are provided for speeding up the cooling of the lubricant as it passes through the tubing. Thus, means is provided for causing a continuous flow of relatively cool air through the region in which the loops of the tubing are housed within the radiator chamber. Such flow of air is created, in the preferred embodiment of the invention, by a fan driven by the same motor which operates the pump. This fan is preferably disposed in an enclosed area at the bottom of the radiator, and it serves to pull in air through a large opening at the front of the radiator and discharges the air from the bottom of the radiator. Another expedient preferably employed to facilitate the cooling of the lubricant is the provision of a large number of relatively thin metal fins extending outwardly from the outer surfaces of the sections of tubing. By virtue of this, the air circulated through the. radiator by the fan picks up heat from the fins and hence from the tubing and the lubricant passing through the latter. If desired, the speed of operation of the lubricant pump and of the air circulating fan may be thermostatically controlled to insure the proper cooling of the lubricant.

With the foregoing objects and features of the invention in mind, an illustrative embodiment of the invention will now be described in some detail in connection with the accompanying drawings in which:

FIG. 1 is a view, partly in elevation and partly in section, of a unit comprising a supporting structure, a sewing machine mounted on the top of said supporting structure, an electric transmitter mounted beneath the sewing machine, and a lubricant cooling system carried by the supporting structure;

FIG. 2 is an elevational view of the apparatus shown in FIG. 1, as seen from the left of the latter;

FIG. 3 is a detail view showing the radiator construction with its cover or Wall, at the right side thereof as shown in FIG. 1, removed to more clearly show the interior devices;

FIG. 4 is a detail view, in plan, of a portion of a pump embodied in the radiator structure of FIG. 1, a top enclosing member of such pump being removed to show the interior construction; and

FIG. 5 is a front elevational view of the sewing machine incorporated in the apparatus disclosed in FIG. 1, with various regions of the frame structure designated by numbers.

Turning now to the drawings, the illustrative embodiment of the invention comprises a work supporting structure having a table top 11, and vertical. supporting or leg elements 12 which are preferably adjustable in height to adapt the machine for most convenient location for a particular operator. The supporting structure also includes a base ortion 12a for engagement with the floor and the retention of the overall structure in a stable condition. A sewing machine 10 is disclosed as mounted on the table top 11. This machine may be of any of a variety of different types, but that illustrated is an overedge type sewing machine of the general character shown in the 3 Wallenberg et al. Patent No. 2,678,013, granted May 11,

1954, with changes in the contour of the outer frame of the character disclosed in the Sullivan design Patent No. 201,107, granted May 11, 1965. As stated above, the invention is adapted for use in connection with a wide variety of sewing machines, but it has some special utility in relation to a system involving an exceptionally high speed sewing machine of the type above-mentioned and illustrated in the drawings. Suitably connected with the under surface of the table top 11 is an electric transmitter 13 which includes a driving motor and a clutch adapted to be rendered effective under the control of the operator by a foot treadle or a knee press or the like. In the drawing, the clutch is shown as being placed into its active position by the downward rocking of a lever arm 14 which has its free end connected with a foot treadle 15 through an adjustable length rod 16; when the foot treadle is rocked downwardly by the foot of the operator, and the lever .14 is rocked in a counterclockwise direction (FIG. 1), the clutch is engaged and the motor of the transmitter drives a pulley 17 which is connected by a belt 18 with a pulley 19 secured to the main shaft of the sewing machine.

The sewing machine 10 is provided with a bottom plate 20 which is secured to the frame of the machine in any suitable manner. This bottom plate has foot elements adapted to fit into openings or depressions provided in the table top 11. Two spaced, threaded openings 21 are provided in the bottom plate 20, and these are adapted to receive coupling members 22 which have a bore through their centers and are provided with a screw threads on their outer end portions adapted to cooperate with the threaded openings in the bottom plate 20. The couplings 22 extend downwardly through openings 22a provided in the table top 11. This enables the connection of tube members 25 and 26 to the respective coupling members 22. These tube members may be formed of any suitable plastic material or of metal. It may be mentioned also that a fan 24 is secured to the main drive shaft of the sewing machine within a chamber 24a in the frame of the machine, this chamber communicating through an opening 24b in the bottom plate 20 with an opening 240 in the table top 11 to provide for the passage of air to or from the fan. This brings about circulation of air through suitable openings in the frame structure to assist in the cooling of the machine in the course of its high speed operation, in the manner explained in the Wallenberg et al. patent above-mentioned.

Now returning to the tube elements 25 and 26, it will be noted in FIG. 1 that these extend toward the left and pass through suitably sealed openings in the wall of a housing 27 of a radiator structure to be described more fully hereinafter. The tube 25 is connected to the inlet side 28a of a pump 28 disposed adjacent the bottom of the housing 27. The outlet 28b from the pump is connected with certain tubing to be described which constitutes the means for cooling the lubricant as it is being circulated by the pump.

As will be seen from FIG. 4, the pump 28 is of a gear type which serves to pick up the lubricant delivered to it through the inlet 28a and discharge it under a suitable pressure through outlet 28b. The latter, as shown in FIG. 3, is connected by a line 29 to a coupling member 30 which is connected with the lower end 31 of a tube 32. The latter is looped upwardly and downwardly and transversely in the various directions indicated in FIGS. 1 and 3 and terminates in a downwardly extending portion 32a at the lower left side, as shown in FIG. 3. This downward extension of the tubing is connected by a coupling member 33 with the tube 26. Thus, the lubricant withdrawn from the reservoir within the machine through line 25 and forced by the action of the pump 28 through the numerous loops of tubing within the radiator housing 27 is returned through the line 26 to the reservoir within the sewing machine. If desired, thermostatic control means may be provided for regulating the speed of operation of the pump 28 in accordance with the temperature of the lubricant in the reservoir of the sewing machine. Thus, the warmer this lubricant becomes the higher may be the sped of operation of the pump to bring about circulation of the lubricant and the desired cooling action. Such thermostatic control will be exercised upon the motor, to be described, which drives the pump.

To facilitate the cooling of the lubricant as it passes through the tubing in the manner described, this tubing is preferably provided with relatively thin flat fins 34 which are in heat transfer contact with the outer surfaces of the various sections of the tubing. It will be understood that the tubing is preferably formed of metal, and so are the fins 34, so that the heat will be transferred rapidly from the lubricant within the tubing to the exposed surfaces of the fins.

For driving the pump 28, there is provided adjacent the base of the chamber 27 a motor 35. The shaft 35a of this motor extends in a vertical direction, both upwardly and downwardly from the housing of the motor, as best shown in FIG. 1. One of the gears, designated 280 in FIG. 4, within the pump 28 is secured to the upwardly extending portion of this shaft, while the downwardly extending portion of the shaft has secured thereto a fan member 36. This serves to bring about rapid circulation of air into and out of the housing 27. Such air is drawn into the housing through an opening 27a at its left side (FIG. 1), and it is caused to flow over the surfaces of the fins 34. The air then passes downwardly through an opening at the bottom of the chamber 27 which is preferably provided with a cylindrical collar 37 around the fan 36. R0- tation of the latter draws the air downwardly from within the chamber 27 and discharges it outwardly away from the latter.

Any suitable connections may be provided for driving the motor 35. As shown in FIGS. 1 and 3, an electrical cable 38, coming from a suitable power source, passes through a 'wall of the chamber 27 and downwardly to the terminals of the motor 35. Any suitable, manually operable switch may be connected with the cable 38 to turn the motor 35 on and off as desired. In the normal use of the apparatus, the switch will be closed to bring about operation of the motor 35 at the commencement of operation of the apparatus and the switch is retained in such closed position until the operator leaves the apparatus. In this connection it should be noted that the motor 35 will thus bring about the pumping of the lubricant through the cooling tubing, and will also bring about the operation of the fan 36, continuously over a period of time, regardless of whether or not the sewing machine is itself actually in operation.

For supporting the motor 35 within the housing 27 at a suitable distance above the lower end of the latter, there is provided a bracket element 39. This has its lower portion secured to the front wall of the housing, i.e., the wall at the left in FIG. 1, by a pair of bolts 40 each carrying a spacing collar 41. The side portions of the bracket element 39 are bent inwardly, at about their midway regions, at an angle of to provide horizontally extending parts 39a (FIGS. 1 and 3). Similarly, an upwardly extending central portion of the bracket element 39 is connected to the left-hand wall of the housing 27 (FIG. 1) by means of a bolt 40 carrying a spacing collar 41. The frame of the motor is secured to the outer ends of the horizontally disposed portions 39a of the bracket member by bolts 42. This mounting of the motor enables the positioning of its shaft in proper relation to the walls of the housing 27, with the pump 28 at its upper end and the fan 36 at its lower end.

Since the sewing machine may be of any of a variety of different types, it is not believed to be necessary to describe its construction in any detail. It is provided with a main drive shaft which carries the pulley 19, as previous ly explained. To this shaft is secured the fan 24 and various crank elements and eccentrics for operating certain parts within the machine. These include the stitch forming elements and the work feeding mechanism. For the lubrication of various elements within the machine, suitable means are provided for distributing lubricant from the reservoir 23 to the surfaces requiring lubrication. Such means, in the machine illustrated, include a plurality of elements 43 which are connected with certain members driven by crank portions of the drive shaft so as to periodically strike into the lubricant within the reservoir and cause it to be sprayed onto the surfaces requiring lubrication. It will be understood that the spray thus created within the enclosed frame of the machine will reach all of the surfaces that need lubrication. During the operation of the machine, as well as when it is stopped, the lubricant will return to the reservoir for reuse.

As shown in FIG. 2 the machine is provided with a presser foot 44 carried by a swingable arm 45 which is urged downwardly by suitable spring means within a housing 46 to apply the desired pressure to retain the work against the cloth plate and the feed dog mechanism of the machine. These aspects of the machine are of well-known character.

Referring now to FIG. 5 of the drawings, this indicates the particular regions of the frame structure of the sewing machine which were themographically investigated to determine the differences between the temperatures at the various points indicated, (1) when the machine was operated without the utilization of the lubricant cooling system of the present invention, and (2) when the machine was operated with the cooling system in action. These tests were conducted when the room temperature in the area in which the machine was located was 73 F. The various points on the frame structure, to which means for determining the temperature were applied, are designated 1, 2, 3, 4, 5 and 6. It was found that when the machine was operated continuously for a period of two hours without the benefit of the cooling system of the present invention, the temperatures at the various points built up to the following:

When the machine was subsequently operated continuously for a period of five hours, with the lubricant cooling system of the present invention in operation, the following temperatures were noted at the various points:

It will be noted from the foregoing that the region of the machine which developed the highest temperature was that designated 2. With the cooling system in operation, the temperature at that point was lowered to the extent to 40 F. The next warmest region of the frame was that designated 4, and here again the cooling system was found to lower the temperature in that area to the extent of about 40 F. It will be appreciated that the tendency of the frame structure to heat up in various regions is due to the frictional and vibratory forces created by the operating of various devices within the machine adjacent those regions. Another point to be observed is that the hottest region of the frame, namely at 2, is quite close to the region in which the operator must move a hand in guiding the work to and through the stitch forming zone. The temperature above 150 F. in that region, when the machine was operated without the cooling system in action, could have been dangerous to the operator, and

would in any event create an uncomfortable temperature for the operator.

While a preferred embodiment of the invention has been shown and described in some detail, it will be understood that various changes may be made in the lubricant cooling system employed, within the scope of the present invention, as defined by the accompanying claims.

What is claimed is:

1. Sewing apparatus comprising a sewing machine having an enclosed frame, a lubricant reservoir within said frame, means for distributing lubricant from said reservoir to bearing surfaces of the machine when the latter is operated, means for operating said machine comprising an electric motor and connections therefrom to said machine including a clutch adapted to be engaged under control of the operator, a radiator adjacent said sewing machine, said radiator having an enclosed chamber, tubing within said chamber arranged in a plurality of loops interconnected in series and substantially filling the space within a portion of said chamber but spaced sufficiently from each other to enable the passage of air around all portions of the tubing, means for causing a continuous flow of air into and out of said chamber at spaced inlet and outlet regions, thereby causing the passage of air around all portions of the tubing, said tubing having the ends thereof connected with said reservoir, a pump arranged to cause circulation of lubricant in a path from said reservoir to and through said radiator and back to said reservoir, and a motor for driving said pump and also said means for causing a continuous flow of air.

2. Sewing apparatus as set forth in claim 1 in which said last mentioned motor has connections therefrom for operating said means for causing said continuous flow of air.

3. Sewing apparatus as set forth in claim 1 in which said tubing has thin metal fins connected therewith and disposed in closely spaced relation to each other, thereby causing said air to pass over and between the surfaces of said fins.

4. Sewing apparatus as set forth in claim 1 in which said last mentioned motor is continuously operated to drive said pump whether or not the sewing machine is in operation.

5. Sewing apparatus as set forth in claim 1 in which said ends of said tubing are connected with openings in the bottom of said reservoir.

6. Sewing apparatus as set forth in claim 1 in which said chamber has an inlet for air in a vertical wall thereof and an outlet for air in a bottom wall thereof.

7. Sewing apparatus as set forth in claim 6 in which said motor for driving said pump is disposed in the lower portion of said chamber.

8. Sewing apparatus as set forth in claim 1 in which said last mentioned motor has a shaft extending outwardly at opposite sides of the frame of said motor, said means for causing said continuous flow of air being connected with said shaft at one side of said frame, and said pump being connected with said shaft at the opposite side of said frame.

9. Sewing apparatus as set forth in claim 6 in which said means for causing said flow of air comprises a fan disposed within said chamber adjacent said outlet.

10. Sewing apparatus as set forth in claim 2 in which the operation of said last mentioned motor is controlled by thermostatic means responsive to the temperature of the lubricant in the reservoir.

11. Sewing apparatus as set forth in claim 6 in which said tubing through which the lubricant is forced by said pump is looped upwardly and downwardly to form at least two series of parallel loops, one series rearwardly of the other in the region of said inlet to said chamber.

12. Sewing apparatus comprising a sewing machine having an enclosed frame, a lubricant reservoir within said frame, means for distributing lubricant from said reservoir to bearing surfaces of the machine when the latter is driven, means for driving said machine, a radiator adjacent said sewing machine, said radiator having an enclosed chamber, fluid conducting passages within said chamber, said passages being so arranged as to enable the flow of air around the external surfaces of the same, means for causing a continuous flow of air into and out of said chamber at spaced inlet and outlet regions, thereby causing the passage of air around said fluid conducting passages, said fluid conducting passages being interconnected in series and having the ends of the continuous passage thus formed connected with said reservoir, a pump arranged to cause circulation of lubricant in a path from said reservoir to and through said radiator and back to said reservoir, and a motor for driving said pump and also said means for causing a continuous flow of air.

References Cited UNITED STATES PATENTS Cunningham 165107 X Zeier et a1. 184-104 X Hacklander 184104 X Shrader 1-65l51- Bono 112-256 Weisz 112-256 X Erbe et a1 165107 US. Cl. X.R. 

